custom ringtomes randomly reset and call log deleted

I keep having a problem where my call log randomly resets (deleting all call history) and where all the customizations I have made to my contacts delete (the contacts are there, but the custom ringtones are reset to default and the custom pictures reset to facebook pictures). This has happened twice for no apparent reason (while my phone is just sitting there).
it is really annoying because I have to go back and re-set all of these things which takes a very long time.

any idea why this is happening or how I can stop it? I couldn't find any other posts about this issue.